A common surgical procedure performed by many surgeons involves the placement of a bone graft, usually secured from the iliac crest or hip bone of a patient, between vertebral bodies after the intervertebral disc material has been removed to eliminate pain and suffering of the patient caused by a diseased or injured disc. One type of instrument used for a similar procedure is shown in U.S. Pat. No. 3,486,505.
The existing surgical method is for a sling to be applied around the patient's neck to distract or separate adjacent vertebral bodies after which an anterior surgical approach is made in the neck usually off to the right side directly over the sternocleiodmastic muscle. The plane of disection is just anterior to the sternocleiodmastoid muscle through the retropharyngeal space whereby the anterior cervical spine is ordinarly reached without great difficulty and certainly without endangering underlying structures. After the level to be fused have been identified, the intervertebral disc material is removed with a knife blade and curette and pituitary rongeurs. These instruments remove the entire disc both nucleus pulposus and anulus fibrosus. A disc space spreader then is applied and the disection is continued with a right angled curette down to the posterior longitudinal ligament and out over both foramina. Retractors then are removed and a drill is used to decorticate the end plates of the vertebral bodies that are to be fused. Once this disection has been completed a bone graft is taken from an exposed iliac crest of the patient and inserted into the formed space between the vertebral bodies earlier occupied by the intervertebral discs.
Heretofore, the size of the bone graft that was removed from the iliac crest was by sight and trial and error with respect to the size of the space formed between the vertebral bodies. Usually the bone graft was cut to a larger size than believed necessary and then sized by trial and error until it fit into the formed space. This required additional time on behalf of the surgeon and could result in an improperly sized graft being placed into the space between the vertebral bodies.
Therefore, the need has existed for a surgical instrument which enables a surgeon to accurately determine the size of bone graft to be removed from the iliac crest for subsequent placement in the space formed between the vertebral bodies to be fused.